Field of the Invention
This specification discloses a technique related to a motor. In particular, this specification discloses a technique related to a motor that is used in an environment having a pressure different from the atmospheric pressure.
Background Art
There is known a motor which is configured to drive a member in a container regulated to a pressure different from the atmospheric pressure, such as a vacuum container. Such a motor is used such that a part of the motor is located in a vacuum and another part of the motor is located in an atmospheric air. JP1991-277148A discloses a motor in which a partition wall is located between a rotor and stator. An environment in a vacuum container and an environment outside the vacuum container are blocked from each other by the partition wall. In the motor of JP1991-277148A, the rotor is located in a vacuum, and the stator is located in an atmospheric air.
In the motor of JP1991-277148A, a pressure difference is generated between a rotor side (vacuum side) of the partition wall and a stator side (atmospheric air side) thereof. This pressure difference applies a force that will deform the partition wall toward the rotor side. Thus, in case the partition wall should be deformed, it is necessary to increase a thickness of the partition wall, and/or it is necessary to elongate a distance between the rotor and the stator in order that the partition wall does not come into contact with the rotor, even if the partition wall is deformed. In either case, the distance between the rotor and stator is long, which increases the motor in size.